Hydrocarbon synthesis from CO and H2 using Ru supported on group VB metal oxides

ABSTRACT

An improved method for the synthesis of hydrocarbons with reduced methane formation and for the selective generation of olefinic hydrocarbons, preferably C 2  -C 5  olefins inclusive, which method comprises the steps of passing a CO and H 2  synthesis gas stream over a catalyst at a temperature and pressure for a time sufficient to generate the desired olefinic products, wherein the improvement consists in using as a catalyst ruthenium on a support comprising at least one refractory Group VB metal oxide. The weight loading of the ruthenium may range from about 0.01 to about 15 wt. % based on the total catalyst weight. The ruthenium average crystallite size is preferably less than 5 nm (50A). The operating conditions of the instant process are typical for Fischer-Tropsch synthesis.

FIELD OF THE INVENTION Brief Description of the Invention

An improved method for the synthesis of hydrocarbons with reduced methane formation and for the selective generation of olefinic hydrocarbons, preferably C₂ -C₅ olefins inclusive, which method comprises the steps of passing a CO and H₂ synthesis gas stream over a catalyst at a temperature and pressure for a time sufficient to generate the desired olefinic products wherein the improvement consists in using as a catalyst ruthenium on a support comprising at least one refractory Group VB metal oxide. The weight loading of the ruthenium may range from about 0.01 to about 15 wt.% based on the weight of the total catalyst. The ruthenium average crystallite size is preferably less than 5 nm (50 A). The operating conditions of the instant process are typical for Fischer-Tropsch synthesis.

DETAILED DESCRIPTION OF THE INVENTION

An improved method for the synthesis of hydrocarbons with reduced methane formation and for the selective generation of olefinic hydrocarbons, preferably C₂ -C₅ olefins inclusive, which method comprises the steps of passing a CO and H₂ synthesis gas stream over a catalyst at a temperature and pressure for a time sufficient to generate the desired olefinic products wherein the improvement consists in using as a catalyst ruthenium on a support comprising at least one refractory Group VB metal oxide.

The instant invention presents an improvement in the Fischer-Tropsch hydrocarbon synthesis method in that it has been discovered unexpectedly that a ruthenium catalyst supported on a refractory Group VB metal oxide, or mixtures thereof, when utilized in conjunction with the Fischer-Tropsch method, will generate, with greater selectivity, olefinic hydrocarbons with reduced production of methane and other paraffinic products.

The instant process exhibits this selectivity to olefinic products, preferably C₂ -C₅ olefins inclusive, when the catalyst utilized comprises ruthenium supported on a supported selected from the group consisting of a refractory Group VB metal oxide, or mixtures thereof, preferably V₂ O₃, Nb₂ O₅ and Ta₂ O₅. The support may also be selected from the group consisting of V₂ O₃, Nb₂ O₅, Ta₂ O₅, Al₂ O₃ -V₂ O₃, Al₂ O₃ -Nb₂ O₅, Al₂ O₃ -Ta₂ O₅, SiO₂ -V₂ O₃, SiO₂ -Ta₂ O₅, SiO₂ -Nb₂ O₅, V₂ O₃ -carbon, Nb₂ O₅ -carbon, Ta₂ O₅ -carbon, alkaline earth-Group VB oxides, alkali-Group VB oxides, rare earth Group VB oxides, Group IVB-Group VB oxides, or mixtures thereof, but is preferably oxides of vanadium, oxides of tantalum and oxides of niobium or mixtures thereof or admixed with alumina, silica or Group IVB oxides. Most preferably, the support comprises essentially pure V₂ O₃, Nb₂ O₅ or Ta₂ O₅ or mixtures thereof either alone or in combination with alumina, silica or Group IVB oxides. It is also possible to admix with these materials other refractory materials that will not substantially inhibit the Fischer-Tropsch hydrocarbon synthesis characteristics of ruthenium supported on at least one Group VB metal oxide as herein described. The supports which may be used in the practice of this invention may be in any form, such as powders, pellets, spheres, extrudates, etc. and may have a B.E.T. surface area of from about 1 to about 200 m² g⁻¹, preferably from about 10 to about 100 m² g⁻¹, most preferably from 25 to about 100 m² g⁻¹. With most metal catalysts, the higher the surface area of the support, the higher the dispersion of the supported metal at a given weight loading. It is therefore desirable to use a support with as high a surface area as possible to maximize the dispersion of the ruthenium metal. Ruthenium is deposited on the chosen support in a concentration of from about 0.01 to about 15 wt.%, preferably from about 0.1 to about 10 wt.%, and most preferably from about 0.5 to about 5 wt.%, the percentages based on total weight of catalyst with the ruthenium possessing an average crystallite size, as determined by standard techniques such as X-ray diffraction of from about 1 to about 20 nm, preferably about 1 to about 10 nm, and most preferably from about 1 to about 5 nm. Using standard experimental techniques, for a ruthenium on Nb₂ O₅ (650), Ta₂ O₅ (650) or V₂ O₃ (650) system, reduced in hydrogen at 450° C., X-ray diffraction shows no particles of Ru in the reduced catalyst, indicating particles of Ru having crystallite sizes of less than 5 nm, which corresponds to a dispersion of greater than 20%.

Ruthenium catalysts comprising ruthenium supported on a support comprising a refractory Group VB metal oxide, or mixtures thereof, exhibit greater selectivity to the production of olefinic products with decreased methane formation as compared with typical ruthenium catalysts of the prior art. The prior art catalysts are either unsupported or supported on such materials as Al₂ O₃, SiO₂ or carbon.

The operating conditions of the instant process are typical for Fischer-Tropsch synthesis. The pressure may range from about 100 to about 10⁵ kPa, preferably from about 100 to about 3100 kPa, and most preferably from about 100 to about 2060 kPa. The temperature may range from about 100° to about 500° C., preferably from about 150° to about 400° C., and most preferably from about 150° to about 300° C. The H₂ /CO ratio may range from about 0.1 to about 10, preferably from about 0.5 to about 4, most preferably from about 1 to about 3. The space velocity may range from about 100 hr⁻¹ to about 50,000 hr⁻¹.

The ruthenium catalysts employed in the practice of the instant process are themselves prepared by techniques known in the art for the preparation of other catalyst systems, such as Ru on Al₂ O₃, etc. A suitable ruthenium salt, such as ruthenium chloride, ruthenium nitrate or ruthenium acetate, etc., is dissolved in a solvent such as water or any other suitable solvent and stirred with the chosen Group VB metal oxide support system. After thorough mixing the mixture is allowed to dry and then heat treated in air at a temperature of from 100° to 150° C. or alternatively may be dried immediately by heating in air at a temperature of between 100° and 150° C. for several hours.

In a preferred embodiment, the ruthenium catalyst, prepared as outlined above, or by similar techniques, is heat treated in a reducing atmosphere such as hydrogen at a temperature greater than 300° C., preferably greater than 400° C., most preferably greater than 500° C., for from typically 0.5 to 4 hours, preferably from 1-2 hours. U.S. Ser. No. 771,396, filed Feb. 23, 1977, copending application of S. J. Tauster, L. L. Murrell and S. C. Fung, teaches the procedures of preparing catalysts by this method and is hereby incorporated by reference. It should be noted that this heat treating reduction step need not be practiced as a separate step, since the Fischer-Tropsch synthesis is practiced in a reducing atmosphere and will, therefore, have a similar reduction effect on the catalyst as the above step. The supported ruthenium catalyst system utilized in the instant process may have an average ruthenium crystallite size of preferably less than 5 nm.

The following examples are presented to illustrate and not limit the instant invention.

EXAMPLE 1

The selectivity in a Fischer-Tropsch synthesis for ruthenium catalysts supported by Nb₂ O₅ is compared to ruthenium catalysts both unsupported and supported by support materials of the prior art.

A 1% Ru/Nb₂ O₅ catalyst was prepared in the following manner. Nb₂ O₅ was prepared by the addition of a methanolic solution of NbCl₅ to a methanolic solution of NH₄ OH, producing a gel. The latter was washed with H₂ O, then with 0.2 M NH₄ NO₃, followed by another wash with H₂ O. This gel was dried at 110° C. The dried gel was calcined in air at 600° C. for 16 hours. X-ray inspection of the calcined product indicated the presence of Nb₂ O₅ with no other phases apparent. The surface area (B.E.T.) was 7.9 m² /g. A portion of Nb₂ O₅ was treated in flowing H₂ (20% in He) at 650° for 11/2 hours. The product was labeled Nb₂ O₅ (650). X-ray inspection showed the presence of Nb₂ O₅ and of NbO₂, the latter being in a lesser amount.

The Nb₂ O₅ and Nb₂ O₅ (650) prepared in the above manner were impregnated by the method of incipient wetness with aqueous solutions of RuCl₃. The impregnates were dried at 110° C. The amount of RuCl₃ used was calculated to provide 1% Ru by total weight of catalyst after reduction in H₂. The RuCl₃ /Nb₂ O₅ was charged after drying into the catalytic reactor for in situ reduction in H₂.

The RuCl₃ /Nb₂ O₅ (650) was treated in flowing H₂ (20% in He) at 650° C., for 11/2 hours, then cooled in flowing He and passivated by treatment with flowing, dilute O₂ (1% in He) at 25° C. This material was thereupon charged into the catalytic reactor where it underwent in situ reduction in H₂.

The ruthenium metal catalyst was prepared as follows. NH₄ OH was added to an aqueous solution of RuCl₃ precipitating Ru(OH)₃ which was subsequently dried at 110°-120° C. in air. It was then charged to the reactor and flushed with He at room temperature. The H₂ concentration in the He stream was slowly increased at a rate such that the sample did not heat up excessively. When 100% H₂ was flowing over the sample, the temperature was increased to 300° C. over a period of 1 hour and held at 300° C. for 1 hour. Subsequently it was cooled to reaction temperature in H₂ for catalytic studies. The ruthenium catalysts supported on carbon, SiO₂ and η-Al₂ O₃ were made in a manner similar to the Ru/Nb₂ O₅ : the ruthenium was deposited on the supports by the incipient wetness technique using RuCl₃ ; they were dried at 110°-120° C. in air; and reduced in situ. The carbon for the ruthenium on carbon catalyst was Carbolac-1, obtained from the Cabot Corporation, had a B.E.T. surface area of 950 m² g⁻¹. The SiO₂ for the ruthenium on SiO₂ catalyst was Cab-O-Sil (HS-5), obtained from the Cabot Corporation, had a B.E.T. surface area of 300 m² g⁻¹. The Al₂ O₃ for the ruthenium on η-Al₂ O₃ was prepared by calcining alumina B-trihydrate (Al₂ O₃.3H₂ O), obtained from Davison Chemical Co., at 600° C. in air for 4 hours. It had a B.E.T. surface area of 245 m² g⁻¹.

                                      TABLE I                                      __________________________________________________________________________     SELECTIVITY OF VARIOUS RUTHENIUM CATALYSTS                                     (Reaction Conditions: H.sub.2 /CO = 3; Pressure = 103 kPa)                                      Hydrocarbon Product Distribution (Mole %)                                  % CO         C.sub.3 H.sub.6                                                                   C.sub.4 H.sub.8                                                                    C.sub.5 H.sub.10                                                                      C.sub.2 -C.sub.5                       Catalyst  T°C.                                                                       Conv                                                                               CH.sub.4                                                                          C.sub.2 H.sub.4                                                                   C.sub.2 H.sub.6                                                                   C.sub.3 H.sub.8                                                                   C.sub.4 H.sub.10                                                                   C.sub.5 H.sub.12                                                                   C.sub.6.sup.+                                                                     Olefins                                                                            C.sub.2.sup.+                      __________________________________________________________________________     Ru metal.sup.c                                                                           226                                                                               3.5 96 0  4  TR.                                                                               0   0   0  0   4                                  4% Ru/Carbon.sup.b                                                                       243                                                                               2.5 98 0  2  TR.                                                                               0   0   0  0   2                                            234                                                                               1.6 98 0  2  0  0   0   0  0   2                                  1% Ru/SiO.sub.2.sup.a                                                                    232                                                                               4.1 87 1/2                                                                               7  4  1   1   TR.                                                                                21/2                                                                              13                                 5% Ru/SiO.sub.2.sup.a                                                                    233                                                                               16.7                                                                               86 TR.                                                                               8  4   11/2                                                                              1   TR.                                                                               TR. 14                                 1% Ru/Al.sub.2 O.sub.3.sup.a                                                             228                                                                               8.8 66                                                            12----                     81/2                                                                             6    41/2                                                                              3  11  34                                           244                                                                               14.1                                                                               71                                                            11----    7  5   4  2     10 29                                                Ru/Al.sub.2 O.sub.3.sup.a                                                                239                                                                               13.6                                                                               67 1/2                                                                               10 10 10  6   5  --  33                                 1% Ru/Nb.sub.2 O.sub.5.sup.a                                                             234                                                                               7.8 48                                                            11----                    13 10  7   12 22  52                                 1% Ru/Nb.sub.2 O.sub.5 (650).sup.a                                                       244                                                                               5.7 41                                                            14----    18 11  11 5     27 59                                                __________________________________________________________________________      .sup.a Catalysts reduced for 1 hour at 450° C. before feed              introduced.                                                                    .sup.b Catalyst reduced for 1 hour at 400° C. before feed               introduced.                                                                    .sup.c Catalyst reduced for 1 hour at 300° C. before feed               introduced.                                                              

Table I illustrates in a Fischer-Tropsch synthesis the desirable selectivity characteristics of Ru/Nb₂ O₅ catalysts as compared with unsupported Ru metal or with catalysts consisting of ruthenium supported on other support materials. In particular, it should be noted that the formation of methane is significantly lower for the Ru/Nb₂ O₅ catalysts than for the other catalysts listed. Thus, whereas the selectivity in the production of C₂ + is up to 34 mole % for all the other catalysts listed in Table I, values up to 59 moles % are obtained for a Ru catalyst supported on Nb₂ O₅. A further desirable feature of the Ru/Nb₂ O₅ catalyst is its enhanced formation of C₂ -C₅ olefins. These olefins are useful chemical intermediates for the production of plastics, rubber, alcohols, ketones, aldehydes, esters and acids. It is shown in Table I that the Ru/Nb₂ O₅ catalysts exhibit at least twice the selectivity in the production of C₂ -C₅ olefins as any other catalyst listed.

EXAMPLE 2

The selectivity in a Fischer-Tropsch synthesis for ruthenium catalysts supported by Ta₂ O₅ is compared to ruthenium catalysts both unsupported and supported by support materials of the prior art.

A 1% Ru/Ta₂ O₅ catalyst was prepared in the following manner. Ta₂ O₅ was prepared by the addition of a methanolic solution of TaCl₅ to a methanolic solution of NH₄ OH, producing a gel. The latter was washed with H₂ O, then with 0.2 M NH₄ NO₃, followed by another wash with H₂ O. This gel was dried at 110° C. The dried gel was calcined in air at 600° C. for 4 hours. X-ray inspection of the calcined product indicated the presence of Ta₂ O₅ with no other phases apparent. The material was recalcined in air at 700° C. for 16 hours. The surface area (B.E.T.) was 5.3 m² /g.

A portion of the Ta₂ O₅ was treated with flowing H₂ (20% in He) at 650° C. for 11/2 hours. The product was labeled Ta₂ O₅ (650). X-ray inspection again showed Ta₂ O₅ with no other phases apparent.

Ta₂ O₅ and Ta₂ O₅ (650) were impregnated by the method of incipient wetness with aqueous solutions of RuCl₃. The amount of RuCl₃ was calculated to provide 1% Ru by weight after reduction in H₂. RuCl₃ /Ta₂ O₅ was charged, after drying, into the catalytic reactor for in situ reduction in H₂.

RuCl₃ /Ta₂ O₅ (650) was treated in flowing H₂ (20% in He) at 650° C., for 11/2 hours, then cooled in flowing He and passivated by treatment with flowing, dilute O₂ (1% in He) 25° C. This material was thereupon charged into the catalytic reactor wherein it underwent in situ activation in H₂. The other catalysts were prepared as described in Example 1.

Table II illustrates in a Fischer-Tropsch synthesis the desirable selectivity characteristics of Ru/Ta₂ O₅ catalysts as compared with unsupported Ru metal or with catalysts consisting of ruthenium supported on other support materials. The other catalysts were prepared as described in Example 1. The data pertaining to Ru metal, Ru/carbon, Ru/SiO₂ and Ru/Al₂ O₃ are identical to that presented in Table I and are repeated for convenience. It is seen that the desirable selectivity characteristics which were pointed out with respect to Ru/Nb₂ O₅ catalysts in Table I also apply to Ru/Ta₂ O₅ catalysts. Thus, the molar selectivities of the Ru/Ta₂ O₅ catalyst in the production of C₂ + hydrocarbons are in excess of 50%--considerably greater than the molar selectivity to the C₂ + hydrocarbons of the prior art catalysts listed. Table II also indicates that the Ru/Ta₂ O₅ catalysts exhibit markedly enhanced selectivity in the production of C₂ -C₅ olefins as compared to any other catalyst listed.

                                      TABLE II                                     __________________________________________________________________________     SELECTIVITY OF VARIOUS RUTHENIUM CATALYSTS                                     (Reaction Conditions: H.sub.2 /CO = 3; Pressure = 103 kPa)                                      Hydrocarbon Product Distribution (Mole %)                               T  % CO         C.sub.3 H.sub.6                                                                   C.sub.4 H.sub.8                                                                    C.sub.5 H.sub.10                                                                      C.sub.2 --C.sub.5                      Catalyst  °C.                                                                        Conv                                                                               CH.sub.4                                                                          C.sub.2 H.sub.4                                                                   C.sub.2 H.sub.6                                                                   C.sub.3 H.sub.8                                                                   C.sub.4 H.sub.10                                                                   C.sub.5 H.sub.12                                                                   C.sub.6.sup.+                                                                     Olefins                                                                            C.sub.2.sup.+                      __________________________________________________________________________     Ru metal.sup.c                                                                           226                                                                               3.5 96 0  4  TR.                                                                               0   0   0  0   4                                  4% Ru/Carbon.sup.b                                                                       243                                                                               2.5 98 0  2  TR.                                                                               0   0   0  0   2                                            234                                                                               1.6 98 0  2  0  0   0   0  0   2                                  1% Ru/SiO.sub.2.sup.a                                                                    232                                                                               4.1 87 1/2                                                                               7  4  1   1   TR.                                                                                21/2                                                                              13                                 5% Ru/SiO.sub.2.sup.a                                                                    233                                                                               16.7                                                                               86 TR.                                                                               8  4   11/2                                                                              1   TR.                                                                               TR. 14                                 1% Ru/Al.sub.2 O.sub.3.sup.a                                                             228                                                                               8.8 66                                                            12----                     81/2                                                                             6    41/2                                                                              3  11  34                                           244                                                                               14.1                                                                               71                                                            11----    7  5   4  2     10 29                                                5% Ru/Al.sub.2 O.sub.3.sup.a                                                             239                                                                               13.6                                                                               67 1/2                                                                               10 10 10  6   5  --  33                                 1% Ru/Ta.sub.2 O.sub.5.sup.a                                                             228                                                                               17.7                                                                               46                                                            10----                    13 10  11  9  17  54                                 1% Ru/Ta.sub.2 O.sub.5 (650).sup.a                                                       226                                                                               10.3                                                                               42                                                            10----    16 12  9  11    27 58                                                __________________________________________________________________________      .sup.a Catalysts reduced for 1 hour at 450° C. before feed              introduced.                                                                    .sup.b Catalyst reduced for 1 hour at 400° C. before feed               introduced.                                                                    .sup.c Catalyst reduced for 1 hour at 300° C. before feed               introduced.                                                              

EXAMPLE 3

The selectivity in a Fischer-Tropsch synthesis for ruthenium catalysts supported by V₂ O₃ is compared to ruthenium catalysts both unsupported and supported by other support materials of the prior art.

A 1% Ru/V₂ O₃ catalyst was prepared in the following manner:

V₂ O₃ was made as follows: NH₄ VO₃ was calcined at about 400° C. in flowing air to give V₂ O₅. The surface area (B.E.T.) was 11 m² /g. The V₂ O₅ was reduced in flowing H₂ (20% in He) at 550° C. for 21/2 hours. X-ray inspection showed V₂ O₃ with a small extraneous signal at 20°=27°. The latter indicates the presence to a very small extent, of a crystallographic shear phase of the family, V_(m) O_(2m-1). The surface area (B.E.T.) was 2.4 m² /g.

A portion of V₂ O₃ was treated in flowing H₂ (20% in He) at 650° C. for 11/2 hours. The product was labelled V₂ O₃ (650). X-ray inspection indicated the presence of V₂ O₃ with no other phases apparent. Thus, the very small amount of higher vanadium oxide present before H₂ treatment at 650° C. had been removed by this treatment.

V₂ O₃ and V₂ O₃ (650) were impregnated by the method of incipient wetness with aqueous solutions of RuCl₃. The impregnates were dried at 110° C. The amount of RuCl₃ used was calculated to provide 1% Ru by weight after reduction in H₂. RuCl₃ /V₂ O₃ was charged, after drying, into the catalytic reactor for in situ reduction in H₂.

RuCl₃ /V₂ O₃ (650) was treated in flowing H₂ (20% in He) at 650° C., 11/2 hours, then cooled in flowing He and passivated by treatment with flowing, dilute O₂ (1% in He) at 25° C. This material was thereupon charged into the catalytic reactor where it underwent in situ activation in H₂.

Table III illustrates in a Fischer-Tropsch synthesis the desirable selectivity characteristics of Ru/V₂ O₃ catalysts as compared with unsupported Ru metal or with catalysts consisting of ruthenium supported on other support materials. The data pertaining to Ru metal, Ru/Carbon, Ru/SiO₂ and Ru/Al₂ O₃ are identical to that presented in Tables I and II and are repeated in Table III for convenience. It is seen that the desirable selectivity characteristics which were demonstrated with respect to Ru/Nb₂ O₅ catalysts in Table I and Ru/Ta₂ O₅ catalysts in Table II also apply to Ru/V₂ O₃ catalysts. Thus, the molar selectivities of the Ru/V₂ O₃ catalysts in the production of C₂ + are about 50%--considerably greater than the molar selectivity to the C₂ + hydrocarbons of the other catalysts listed. Formation of C₂ -C₅ olefins is also markedly enhanced for Ru/V₂ O₃. In the case of Ru/V₂ O₃ (650), formation of propylene, butene and pentene was not measured. However, the high selectivity with which ethylene is formed by this catalyst (17% or 16%, as compared with 1/2% over 5% Ru/Al₂ O₃) is significant.

                                      TABLE III                                    __________________________________________________________________________     SELECTIVITY OF VARIOUS RUTHENIUM CATALYSTS                                     (Reaction Conditions: H.sub.2 /CO = 3, Pressure = 103 kPa)                                      Hydrocarbon Product Distribution (Mole %)                               T  % CO         C.sub.3 H.sub.6                                                                   C.sub.4 H.sub.8                                                                    C.sub.5 H.sub.10                                                                      C.sub.2 -C.sub.5                       Catalyst  °C.                                                                        Conv                                                                               CH.sub.4                                                                          C.sub.2 H.sub.4                                                                   C.sub.2 H.sub.6                                                                   C.sub.3 H.sub.8                                                                   C.sub.4 H.sub.10                                                                   C.sub.5 H.sub.12                                                                   C.sub.6.sup.+                                                                     Olefins                                                                            C.sub.2.sup.+                      __________________________________________________________________________     Ru metal.sup.c                                                                           226                                                                               3.5 96 0  4  TR.                                                                               0   0   0  0   4                                  4% Ru/Carbon.sup.b                                                                       243                                                                               2.5 98 0  2  TR.                                                                               0   0   0  0   2                                            234                                                                               1.6 98 0  2  0  0   0   0  0   2                                  1% Ru/SiO.sub.2.sup.a                                                                    232                                                                               4.1 87 1/2                                                                               7  4  1   1   TR.                                                                                21/2                                                                              13                                 5% Ru/SiO.sub.2.sup.a                                                                    233                                                                               16.7                                                                               86 TR.                                                                               8  4  11/2                                                                               1   TR.                                                                               TR. 14                                 1% Ru/Al.sub.2 O.sub.3.sup.a                                                             228                                                                               8.8 66                                                            12----                     81/2                                                                             6   41/2                                                                               3  11  34                                           244                                                                               14.1                                                                               71                                                            11----    7  5   4  2     10 29                                                5% Ru/Al.sub.2 O.sub.3.sup.a                                                             239                                                                               13.6                                                                               67 1/2                                                                               10 10 10  6   5  --  33                                 1% Ru/V.sub.2 O.sub.3.sup.a                                                              243                                                                               4.1 45 6  9  18 10  3   10 28  55                                 1% Ru/V.sub.2 O.sub.3 (650).sup.a                                                        246                                                                               0.7 55 17 4  17 6   --  -- --  45                                           259                                                                               1.4 49 16 5  17 6   8   -- --  51                                 __________________________________________________________________________      .sup.a Catalysts reduced for 1 hour at 450° C. before feed              introduced                                                                     .sup.b Catalyst reduced for 1 hour at 400° C. before feed               introduced                                                                     .sup.c Catalyst reduced for 1 hour at 300° C. before feed               introduced                                                                

What is claimed is:
 1. A process for the synthesis of olefins of from C₂ to C₅ chain length inclusive, said process comprising the steps of passing H₂ and CO at a H₂ /CO ratio of 0.1 to about 10 over a catalyst comprising ruthenium on a support selected from the group consisting of V₂ O₃, Nb₂ O₅, Ta₂ O₅, Al₂ O₃ -V₂ O₃, Al₂ O₃ -Nb₂ O₅, Al₂ O₃ -Ta₂ O₅, SiO₂ -V₂ O₃, SiO₂ -Nb₂ O₅, SiO₂ -Ta₂ O₅, V₂ O₃ -carbon, Nb₂ O₅ -carbon, Ta₂ O₅ -carbon, alkaline earth-group VB oxides, alkali-Group VB oxides, rare earth-Group VB oxides, Group IVB-Group VB oxides and mixtures thereof, at a space velocity of from 100 to 50,000 hr⁻¹ , at a temperature of from 100° to 500° C., at a pressure of from 100 to 10⁵ kPa for a time sufficient to effect the generation of the desired olefinic products wherein the concentration of said ruthenium in said catalyst is from 0.01 to 15 wt. % based on total catalyst weight.
 2. The process of claim 1 wherein the support comprising a Group VB metal oxide or mixture thereof is selected from the group consisting of V₂ O₃, Nb₂ O₅, Ta₂ O₅, Al₂ O₃ -V₂ O₃, Al₂ O₃ -Nb₂ O₅, Al₂ O₃ -Ta₂ O₅, SiO₂ -V₂ O₃, SiO₂ -Nb₂ O₅, SiO₂ -Ta₂ O₅, V₂ O₃ -carbon, Nb₂ O₅ -carbon, Ta₂ O₅ -carbon, alkaline earth-Group VB oxides, alkali-Group VB oxides, rare earth-Group VB oxides, Group IVB-Group VB oxides and mixtures thereof.
 3. The process of claim 1 wherein the Group VB metal oxide is selected from the group consisting of V₂ O₃, Nb₂ O₅, Ta₂ O₅, and mixtures thereof.
 4. The process of claim 1 wherein the Group VB metal oxide is V₂ O₃.
 5. The process of claim 1 wherein the group VB metal oxide is Nb₂ O₅.
 6. The process of claim 1 wherein the group VB metal oxide is Ta₂ O₅.
 7. The process of claim 1 wherein the ruthenium concentration is from about 0.1 to about 10 wt. % based on the total weight of the catalyst.
 8. The process of claim 7 wherein the ruthenium concentration is from about 0.5 to about 5 wt. % based on the total weight of the catalyst.
 9. The process of claim 2 wherein said ruthenium supported catalyst has a ruthenium particle crystallite size of from about 1 to about 20 nm.
 10. The process of claim 9 wherein said ruthenium particle crystallite size is from about 1 to about 10 nm.
 11. The process of claim 10 wherein said ruthenium particle crystallite size is from about 1 to about 5 nm.
 12. The process of claim 1 wherein the catalyst is reduced at a temperature of greater than 300° C.
 13. The process of claim 1 wherein the support has a surface area of from about 1 to about 200 m² g⁻¹.
 14. The process of claim 1 wherein the H₂ /CO ratio is about 0.5 to about 4, the pressure is from about 100 to 3100 kPa and the temperature is about 150° to about 400° C.
 15. The process of claim 1 wherein the H₂ /CO ratio is about 1 to about 3, the pressure is from about 100 to about 2060 kPa and the temperature is about 150° to about 300° C.
 16. The process of claim 14 wherein the support is Nb₂ O₅.
 17. The process of claim 14 wherein the support is Ta₂ O₅. 